Page 36 - MetalForming May 2011

Abrasive Belt,
Demagnetizer Prove Key to
New Conveying
Solution
...at metalformer Buhrke Industries, which now can confidently supply critical, assembled airbag housings to its customer with an annual production volume in excess of 350,000.
Imagine trying to paint a surface sprinkled in saw dust. Obviously, before completing your first swipe of the brush you’ll need to clean the surface so it’s smooth and free of debris.
Buhrke Industries, an Arlington Heights, IL, a stamper/assembler and Tier One supplier to the automotive industry, experienced a similar chal- lenge when manufacturing a custom part for an automotive-airbag assem- bly. Throughout the manufacturing process, the stamped assembly housing was becoming magnetized. As a result, the housing would attract small metal- lic dust and other particles, affecting overall appearance.
“When our customer would apply an e-coating to the part, these foreign particles often would result in a rough, substandard finish,” says Steve Amaro, a process engineer at Buhrke. “Clearly, we needed to demagnetize the parts to leave them with a smooth finish for
the coating process, to make our cus- tomer happy.”
Magnetics—Cause and Effect
Amaro blames the magnetization issue on the company’s robotic-welding process used to assemble the airbag housing. To solve the problem, Amaro added a demagnetizer to the housing’s production line, and a conveyor to help improve product flow.
Initially, the robotically welded airbag housing assemblies traveled down a chute and collected together on a table. Often, the parts would back up into one another before each was individually inspected. Buhrke installed a demagnetizer at the chute, however this created another issue for Amaro: the housing assemblies needed to trav- el a few feet away from the demagnet- izer so as to not interfere with its oper- ation. Existing product flow slid the assemblies onto the table only about 8
in. from the demagnetizer. A distance of 3 ft. was preferred.
The solution: Install a conveyor into the table that collects the housing assem- blies as they slide down the chute, mov- ing them away from the demagnetizer. To do so, Buhrke technicians cut out a space on the table to make room for a repurposed, spare conveyor the firm had inhouse (a Dorner 2200 Series cen- ter-drive model). The conveyor belt sits flush with the table. Two tall guide strips mount on the table alongside the 3-ft.- long, 6-in.-wide conveyor to keep hous- ing assemblies positioned straight on the belt as they discharge onto the table.
Getting a Better Grip
The conveyor worked as anticipat- ed, but Amaro soon noticed that parts still would back up on the conveyor and fail to travel the proper distance away from the demagnetizer. As assem- bly housings began backing up on the
34 MetalForming/May 2011
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A Dorner conveyor with a new, high- friction belt moves welded airbag- housing assem- blies away from
a demagnetizer.